Compound having acridan ring structure, and organic electroluminescent device

ABSTRACT

An organic compound with characteristics excelling in hole-injecting/transporting performance and having an electron blocking ability, a highly stable thin-film state, and excellent heat resistance is provided as material for an organic electroluminescent device of high efficiency and high durability, and the organic electroluminescent device of high efficiency and high durability is provided using this compound. The compound of a general formula (Chemical Formula 1) having a substituted acridan ring structure is used as a constituent material of at least one organic layer in the organic electroluminescent device that includes a pair of electrodes and one or more organic layers sandwiched between the pair of electrodes.

TECHNICAL FIELD

The present invention relates to compounds suitable for an organicelectroluminescent device which is a preferred self-luminous device forvarious display devices, and relates to the organic electroluminescentdevice. Specifically, this invention relates to compounds having anacridan ring structure, and organic electroluminescent devices using thecompounds.

BACKGROUND ART

The organic electroluminescent device is a self-luminous device and hasbeen actively studied for their brighter, superior visibility and theability to display clearer images in comparison with liquid crystaldevices.

In 1987, C. W. Tang and colleagues at Eastman Kodak developed alaminated structure device using materials assigned with differentroles, realizing practical applications of an organic electroluminescentdevice with organic materials. These researchers laminated anelectron-transporting phosphor which is tris(8-hydroxyquinoline)aluminum(hereinafter referred to as Alq₃) and a hole-transporting aromatic aminecompound, and injected both charges into a phosphor layer to causeemission in order to obtain a high luminance of 1,000 cd/m² or more at avoltage of 10 V or less (refer to Patent Documents 1 and 2, forexample).

To date, various improvements have been made for practical applicationsof the organic electroluminescent device. In order to realize highefficiency and durability, various roles are further subdivided toprovide an electroluminescence device that includes an anode, a holeinjection layer, a hole transport layer, a light emitting layer, anelectron transport layer, an electron injection layer, and a cathodesuccessively formed on a substrate (refer to Non-Patent Document 1, forexample).

Further, there have been attempts to use triplet excitons for furtherimprovements of luminous efficiency, and the use of phosphorescentmaterials has been examined (refer to Non-Patent Document 2, forexample).

The light emitting layer can be also fabricated by doping acharge-transporting compound generally called a host material, with aphosphor or a phosphorescent material. As described in the foregoinglecture preprints, the selection of organic materials in an organicelectroluminescent device greatly influences various devicecharacteristics such as efficiency and durability.

In an organic electroluminescent device, charges injected from bothelectrodes recombine in a light emitting layer to cause emission. Whatis important here is how efficiently the hole and electron charges aretransferred to the light emitting layer. The probability ofhole-electron recombination can be improved by improving holeinjectability and electron blocking performance of blocking injectedelectrons from the cathode, and high luminous efficiency can be obtainedby confining excitons generated in the light emitting layer. The role ofa hole transport material is therefore important, and there is a needfor a hole transport material that has high hole injectability, highhole mobility, high electron blocking performance, and high durabilityto electrons.

Heat resistance and amorphousness of the materials are also importantwith respect to a lifetime of the device. The materials with low heatresistance cause thermal decomposition even at a low temperature by heatgenerated during the drive of the device, which leads to thedeterioration of the materials. The materials with low amorphousnesscause crystallization of a thin film even in a short time and lead tothe deterioration of the device. The materials in use are thereforerequired to have characteristics of high heat resistance andsatisfactory amorphousness.

N,N′-diphenyl-N,N′-di(a-naphthyl)benzidine (hereinafter referred to asNPD) and various aromatic amine derivatives are known as the holetransport materials used for the organic electroluminescent device(refer to Patent Documents 1 and 2, for example). Although NPD hasdesirable hole transportability, it has a low glass transition point(Tg) of 96° C. which is an index of heat resistance and therefore causesthe degradation of device characteristics by crystallization under ahigh-temperature condition (refer to Non-Patent Document 3, forexample). The aromatic amine derivatives described in the PatentDocuments 1 and 2 include a compound known to have an excellent holemobility of 10⁻³ cm²/Vs or higher. However, since the compound isinsufficient in terms of electron blocking performance, some of theelectrons pass through the light emitting layer, and improvements inluminous efficiency cannot be expected. For such a reason, a materialwith higher electron blocking performance, a more stable thin-film stateand higher heat resistance is needed for higher efficiency.

Arylamine compounds of the following formulae having a substitutedacridan structure (for example, Compounds A and B) are proposed ascompounds improved in the characteristics such as heat resistance, holeinjectability and electron blocking performance (refer to PatentDocuments 3 and 4, for example).

However, while the devices using these compounds for the hole injectionlayer or the hole transport layer have been improved in heat resistance,luminous efficiency and the like, the improvements are stillinsufficient. Further, it cannot be said to have a sufficiently lowdriving voltage and sufficient current efficiency, and there is aproblem also in amorphousness. Further improvements of a low drivingvoltage and luminous efficiency while increasing amorphousness aretherefore needed.

CITATION LIST Patent Documents

-   Patent Document 1: JP-A-8-48656-   Patent Document 2: Japanese Patent No. 3194657-   Patent Document 3: WO2006/033563-   Patent Document 4: WO2007/110228

Non-Patent Documents

-   Non-Patent Document 1: The Japan Society of Applied Physics, 9th    Lecture Preprints, pp. 55 to 61 (2001)-   Non-Patent Document 2: The Japan Society of Applied Physics, 9th    Lecture Preprints, pp. 23 to 31 (2001)-   Non-Patent Document 3: Organic EL Symposium, the 3rd Regular    presentation Preprints, pp. 13 to 14 (2006)-   Non-Patent Document 4: J. Org. Chem., 60, 7508 (1995)-   Non-Patent Document 5: Chem. Rev., 95, 2457 (1995)-   Non-Patent Document 6: Angew. Chem. Int. Ed., 42, 5400 (2003)

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

An object of the present invention is to provide an organic compoundwith characteristics excelling in hole-injecting/transportingperformance and having electron blocking ability, high stability in athin-film state and excellent heat resistance, the organic compoundbeing provided as material for an organic electroluminescent devicehaving high efficiency and high durability. This invention also providesthe organic electroluminescent device of high efficiency and highdurability using this compound.

Physical properties of the organic compound to be provided by thepresent invention include (1) good hole injection characteristics, (2)large hole mobility, (3) excellent electron blocking ability, (4)stability in the thin-film state, and (5) excellent heat resistance.Physical properties of the organic electroluminescent device to beprovided by the present invention include (1) high luminous efficiencyand high power efficiency, (2) low turn on voltage, and (3) low actualdriving voltage.

In order to achieve the above objects, the present inventors designedcompounds having an acridan ring structure in anticipation of the highhole-injecting/transporting ability of an aromatic tertiary aminestructure, the electron blocking performance of the acridan ringstructure, and the effect of heat resistance and thin-film stability ofthese partial structures. The present inventors produced various testorganic electroluminescent devices using the compounds chemicallysynthesized to have the acridan ring structure, and the presentinvention was'completed after thorough evaluations of the devicecharacteristics.

Specifically, the present invention is a compound of the followinggeneral formula (1) having a substituted acridan ring structure.

In the formula, A represents a divalent group of a substituted orunsubstituted aromatic hydrocarbon, a divalent group of a substituted orunsubstituted aromatic heterocyclic ring, or a divalent group ofsubstituted or unsubstituted condensed polycyclic aromatics. Ar1, Ar2,and Ar3 may be the same or different, and represent a substituted orunsubstituted aromatic hydrocarbon group, a substituted or unsubstitutedaromatic heterocyclic group, or a substituted or unsubstituted condensedpolycyclic aromatic group. Ar2 and Ar3 may directly bind to each othervia a single bond or via substituted or unsubstituted methylene, anoxygen atom, or a sulfur atom to form a ring, and substituents of Ar2and Ar3 may bind to each other via a single bond, substituted orunsubstituted methylene, an oxygen atom, or a sulfur atom to form aring. R1 to R7 may be the same or different, and represent a hydrogenatom, a deuterium atom, a fluorine atom, a chlorine atom, cyano,trifluoromethyl, nitro, linear or branched alkyl of 1 to 6 carbon atomsthat may have a substituent, cycloalkyl of 5 to 10 carbon atoms that mayhave a substituent, linear or branched alkenyl of 2 to 6 carbon atomsthat may have a substituent, linear or branched alkyloxy of 1 to 6carbon atoms that may have a substituent, cycloalkyloxy of 5 to 10carbon atoms that may have a substituent, a substituted or unsubstitutedaromatic hydrocarbon group, a substituted or unsubstituted aromaticheterocyclic group, a substituted or unsubstituted condensed polycyclicaromatic group, or substituted or unsubstituted aryloxy, which may bindto each other via a single bond, substituted or unsubstituted methylene,an oxygen atom, or a sulfur atom to form a ring. R8 and R9 may be thesame or different, and represent trifluoromethyl, linear or branchedalkyl of 1 to 6 carbon atoms that may have a substituent, cycloalkyl of5 to 10 carbon atoms that may have a substituent, linear or branchedalkenyl of 2 to 6 carbon atoms that may have a substituent, linear orbranched alkyloxy of 1 to 6 carbon atoms that may have a substituent,cycloalkyloxy of 5 to 10 carbon atoms that may have a substituent, asubstituted or unsubstituted aromatic hydrocarbon group, a substitutedor unsubstituted aromatic heterocyclic group, a substituted orunsubstituted condensed polycyclic aromatic group, or substituted orunsubstituted aryloxy, which may bind to each other via a single bond,substituted or unsubstituted methylene, an oxygen atom, or a sulfur atomto form a ring.

Further, the present invention is a compound of the following generalformula (2) having a substituted acridan ring structure.

In the formula, A represents a divalent group of substituted orunsubstituted aromatic hydrocarbon, a divalent group of a substituted orunsubstituted aromatic heterocyclic ring, or a divalent group ofsubstituted or unsubstituted condensed polycyclic aromatics. Ar1, Ar2,and Ar3 may be the same or different, and represent a substituted orunsubstituted aromatic hydrocarbon group, a substituted or unsubstitutedaromatic heterocyclic group, or a substituted or unsubstituted condensedpolycyclic aromatic group. Ar2 and Ar3 may directly bind to each othervia a single bond or via substituted or unsubstituted methylene, anoxygen atom, or a sulfur atom to form a ring, and substituents of Ar2and Ar3 may bind to each other via a single bond, substituted orunsubstituted methylene, an oxygen atom, or a sulfur atom to form aring. R1 to R7 may be the same or different, and represent a hydrogenatom, a deuterium atom, a fluorine atom, a chlorine atom, cyano,trifluoromethyl, nitro, linear or branched alkyl of 1 to 6 carbon atomsthat may have a substituent, cycloalkyl of 5 to 10 carbon atoms that mayhave a substituent, linear or branched alkenyl of 2 to 6 carbon atomsthat may have a substituent, linear or branched alkyloxy of 1 to 6carbon atoms that may have a substituent, cycloalkyloxy of 5 to 10carbon atoms that may have a substituent, a substituted or unsubstitutedaromatic hydrocarbon group, a substituted or unsubstituted aromaticheterocyclic group, a substituted or unsubstituted condensed polycyclicaromatic group, or substituted or unsubstituted aryloxy, which may bindto each other via a single bond, substituted or unsubstituted methylene,an oxygen atom, or a sulfur atom to form a ring. R8 and R9 may be thesame or different, and represent trifluoromethyl, linear or branchedalkyl of 1 to 6 carbon atoms that may have a substituent, cycloalkyl of5 to 10 carbon atoms that may have a substituent, linear or branchedalkenyl of 2 to 6 carbon atoms that may have a substituent, linear orbranched alkyloxy of 1 to 6 carbon atoms that may have a substituent,cycloalkyloxy of 5 to 10 carbon atoms that may have a substituent, asubstituted or unsubstituted aromatic hydrocarbon group, a substitutedor unsubstituted aromatic heterocyclic group, a substituted orunsubstituted condensed polycyclic aromatic group, or substituted orunsubstituted aryloxy, which may bind to each other via a single bond,substituted or unsubstituted methylene, an oxygen atom, or a sulfur atomto form a ring.

Further, the present invention is a compound of the following generalformula (3) having a substituted acridan ring structure.

In the formula, Ar1, Ar2, and Ar3 may be the same or different, andrepresent a substituted or unsubstituted aromatic hydrocarbon group, asubstituted or unsubstituted aromatic heterocyclic group, or asubstituted or unsubstituted condensed polycyclic aromatic group. Ar2and Ar3 may directly bind to each other via a single bond or viasubstituted or unsubstituted methylene, an oxygen atom, or a sulfur atomto form a ring, and substituents of Ar2 and Ar3 may bind to each othervia a single bond, substituted or unsubstituted methylene, an oxygenatom, or a sulfur atom to form a ring. R1 to R7 and R10 to R13 may bethe same or different, and represent a hydrogen atom, a deuterium atom,a fluorine atom, a chlorine atom, cyano, trifluoromethyl, nitro, linearor branched alkyl of 1 to 6 carbon atoms that may have a substituent,cycloalkyl of 5 to 10 carbon atoms that may have a substituent, linearor branched alkenyl of 2 to 6 carbon atoms that may have a substituent,linear or branched alkyloxy of 1 to 6 carbon atoms that may have asubstituent, cycloalkyloxy of 5 to 10 carbon atoms that may have asubstituent, a substituted or unsubstituted aromatic hydrocarbon group,a substituted or unsubstituted aromatic heterocyclic group, asubstituted or unsubstituted condensed polycyclic aromatic group, orsubstituted or unsubstituted aryloxy, wherein R1 and R2, R2 and R3, R3and R4, R6 and R7, R10 and R11, and R12 and R13 may bind to each othervia a single bond, substituted or unsubstituted methylene, an oxygenatom, or a sulfur atom to form a ring. R8 and R9 may be the same ordifferent, and represent trifluoromethyl, linear or branched alkyl of 1to 6 carbon atoms that may have a substituent, cycloalkyl of 5 to 10carbon atoms that may have a substituent, linear or branched alkenyl of2 to 6 carbon atoms that may have a substituent, linear or branchedalkyloxy of 1 to 6 carbon atoms that may have a substituent,cycloalkyloxy of 5 to 10 carbon atoms that may have a substituent, asubstituted or unsubstituted aromatic hydrocarbon group, a substitutedor unsubstituted aromatic heterocyclic group, a substituted orunsubstituted condensed polycyclic aromatic group, or substituted orunsubstituted aryloxy, which may bind to each other via a single bond,substituted or unsubstituted methylene, an oxygen atom, or a sulfur atomto form a ring.

Further, the present invention is a compound of the following generalformula (4) having a substituted acridan ring structure.

In the formula, A represents a divalent group of a substituted orunsubstituted aromatic hydrocarbon, a divalent group of a substituted orunsubstituted aromatic heterocyclic ring, or a divalent group ofsubstituted or unsubstituted condensed polycyclic aromatics. Ar2 and Ar3may be the same or different, and represent a substituted orunsubstituted aromatic hydrocarbon group, a substituted or unsubstitutedaromatic heterocyclic group, or a substituted or unsubstituted condensedpolycyclic aromatic group. Ar2 and Ar3 may directly bind to each othervia a single bond or via substituted or unsubstituted methylene, anoxygen atom, or a sulfur atom to form a ring, and substituents of Ar2and Ar3 may bind to each other via a single bond, substituted orunsubstituted methylene, an oxygen atom, or a sulfur atom to form aring. R1 to R7 and R14 to R18 may be the same or different, andrepresent a hydrogen atom, a deuterium atom, a fluorine atom, a chlorineatom, cyano, trifluoromethyl, nitro, linear or branched alkyl of 1 to 6carbon atoms that may have a substituent, cycloalkyl of 5 to 10 carbonatoms that may have a substituent, linear or branched alkenyl of 2 to 6carbon atoms that may have a substituent, linear or branched alkyloxy of1 to 6 carbon atoms that may have a substituent, cycloalkyloxy of 5 to10 carbon atoms that may have a substituent, a substituted orunsubstituted aromatic hydrocarbon group, a substituted or unsubstitutedaromatic heterocyclic group, a substituted or unsubstituted condensedpolycyclic aromatic group, or substituted or unsubstituted aryloxy,wherein R1 and R2, R2 and R3, R3 and R4, R6 and R7, R14 and R15, R15 andR16, R16 and R17, and R17 and R18 may bind to each other via a singlebond, substituted or unsubstituted methylene, an oxygen atom, or asulfur atom to form a ring. R8 and R9 may be the same or different, andrepresent trifluoromethyl, linear or branched alkyl of 1 to 6 carbonatoms that may have a substituent, cycloalkyl of 5 to 10 carbon atomsthat may have a substituent, linear or branched alkenyl of 2 to 6 carbonatoms that may have a substituent, linear or branched alkyloxy of 1 to 6carbon atoms that may have a substituent, cycloalkyloxy of 5 to 10carbon atoms that may have a substituent, a substituted or unsubstitutedaromatic hydrocarbon group, a substituted or unsubstituted aromaticheterocyclic group, a substituted or unsubstituted condensed polycyclicaromatic group, or substituted or unsubstituted aryloxy, which may bindto each other via a single bond, substituted or unsubstituted methylene,an oxygen atom, or a sulfur atom to form a ring.

Further, the present invention is an organic electroluminescent devicethat includes a pair of electrodes and one or more organic layerssandwiched between the pair of electrodes, wherein the compound of thegeneral formula (1), (2), (3), or (4) having a substituted acridan ringstructure is used as a constituent material of at least one organiclayer.

Specific examples of the “linear or branched alkyl of 1 to 6 carbonatoms”, the “cycloalkyl of 5 to 10 carbon atoms”, or the “linear orbranched alkenyl of 2 to 6 carbon atoms” in the “linear or branchedalkyl of 1 to 6 carbon atoms that may have a substituent”, the“cycloalkyl of 5 to 10 carbon atoms that may have a substituent”, or the“linear or branched alkenyl of 2 to 6 carbon atoms that may have asubstituent” represented by R1 to R18 in general formulae (1) to (4),can be methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl,tert-butyl, n-pentyl, isopentyl, neopentyl, n-hexyl, cyclopentyl,cyclohexyl, 1-adamantyl, 2-adamantyl, vinyl, allyl, isopropenyl, and2-butenyl. These groups may bind to each other via a single bond,substituted or unsubstituted methylene, an oxygen atom, or a sulfur atomto form a ring.

Specific examples of the “substituent” in the “linear or branched alkylof 1 to 6 carbon atoms that has a substituent”, the “cycloalkyl of 5 to10 carbon atoms that has a substituent”, or the “linear or branchedalkenyl of 2 to 6 carbon atoms that has a substituent” represented by R1to R18 in general formulae (1) to (4) can be a deuterium atom;trifluoromethyl; cyano; nitro; halogen atoms such as a fluorine atom, achlorine atom, a bromine atom, and an iodine atom; linear or branchedalkoxys of 1 to 6 carbon atoms such as methoxy, ethoxy, and propyloxy;alkenyls such as allyl; aryloxys such as phenoxy and tolyloxy;arylalkoxys such as benzyloxy and phenethyloxy; aromatic hydrocarbongroups or condensed polycyclic aromatic groups such as phenyl,biphenylyl, terphenylyl, naphthyl, anthracenyl, phenanthryl, fluorenyl,indenyl, pyrenyl, perylenyl, fluoranthenyl, and triphenylenyl; andaromatic heterocyclic groups such as pyridyl, furanyl, pyranyl, thienyl,furyl, pyrrolyl, thienyl, quinolyl, isoquinolyl, benzofuranyl,benzothienyl, indolyl, carbazolyl, benzooxazolyl, benzothiazolyl,quinoxalyl, benzoimidazolyl, pyrazolyl, dibenzofuranyl, dibenzothienyl,and carbolinyl. These substituents may be further substituted with othersubstituents. These substituents may bind to each other via a singlebond, substituted or unsubstituted methylene, an oxygen atom, or asulfur atom to form a ring.

Specific examples of the “linear or branched alkyloxy of 1 to 6 carbonatoms” or the “cycloalkyloxy of to 10 carbon atoms” in the “linear orbranched alkyloxy of 1 to 6 carbon atoms that may have a substituent” orthe “cycloalkyloxy of 5 to 10 carbon atoms that may have a substituent”represented by R1 to R18 in general formulae (1) to (4) can bemethyloxy, ethyloxy, n-propyloxy, isopropyloxy, n-butyloxy,tert-butyloxy, n-pentyloxy, n-hexyloxy, cyclopentyloxy, cyclohexyloxy,cycloheptyloxy, cyclooctyloxy, 1-adamantyloxy, and 2-adamantyloxy. Thesegroups may bind to each other via a single bond, substituted orunsubstituted methylene, an oxygen atom, or a sulfur atom to form aring.

Specific examples of the “substituent” in the “linear or branchedalkyloxy of 1 to 6 carbon atoms that has a substituent” or the“cycloalkyloxy of 5 to 10 carbon atoms that has a substituent”represented by R1 to R18 in general formulae (1) to (4) can be adeuterium atom; trifluoromethyl; cyano; nitro; halogen atoms such as afluorine atom, a chlorine atom, a bromine atom, and an iodine atom;linear or branched alkoxys of 1 to 6 carbon atoms such as methoxy,ethoxy, and propyloxy; alkenyls such as allyl; aryloxys such as phenoxyand tolyloxy; arylalkoxys such as benzyloxy and phenethyloxy; aromatichydrocarbon groups or condensed polycyclic aromatic groups such asphenyl, biphenylyl, terphenylyl, naphthyl, anthracenyl, phenanthryl,fluorenyl, indenyl, pyrenyl, perylenyl, fluoranthenyl, andtriphenylenyl; and aromatic heterocyclic groups such as pyridyl,furanyl, pyranyl, thienyl, furyl, pyrrolyl, thienyl, quinolyl,isoquinolyl, benzofuranyl, benzothienyl, indolyl, carbazolyl,benzooxazolyl, benzothiazolyl, quinoxalyl, benzoimidazolyl, pyrazolyl,dibenzofuranyl, dibenzothienyl, and carbolinyl. These substituents maybe further substituted with other substituents. These substituents maybind to each other via a single bond, substituted or unsubstitutedmethylene, an oxygen atom, or a sulfur atom to form a ring.

Specific examples of the “aromatic hydrocarbon group”, the “aromaticheterocyclic group”, or the “condensed polycyclic aromatic group” in the“substituted or unsubstituted aromatic hydrocarbon group”, the“substituted or unsubstituted aromatic heterocyclic group”, or the“substituted or unsubstituted condensed polycyclic aromatic group”represented by R1 to R18 in general formulae (1) to (4) can be phenyl,biphenylyl, terphenylyl, naphthyl, anthryl, phenanthryl, fluorenyl,indenyl, pyrenyl, perylenyl, fluoranthenyl, triphenylenyl, pyridyl,furanyl, pyranyl, thienyl, quinolyl, isoquinolyl, benzofuranyl,benzothienyl, indolyl, carbazolyl, benzooxazolyl, benzothiazolyl,quinoxalyl, benzoimidazolyl, pyrazolyl, dibenzofuranyl, dibenzothienyl,and carbolinyl. These groups may bind to each other via a single bond,substituted or unsubstituted methylene, an oxygen atom, or a sulfur atomto form a ring.

Specific examples of the “substituent” in the “substituted aromatichydrocarbon group”, the “substituted aromatic heterocyclic group”, orthe “substituted condensed polycyclic aromatic group” represented by R1to R18 in general formulae (1) to (4) can be a deuterium atom;trifluoromethyl; cyano; nitro; halogen atoms such as a fluorine atom, achlorine atom, a bromine atom, and an iodine atom; linear or branchedalkyls of 1 to 6 carbon atoms such as methyl, ethyl, n-propyl,isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl,neopentyl, and n-hexyl; linear or branched alkoxys of 1 to 6 carbonatoms such as methoxy, ethoxy, and propyloxy; alkenyls such as allyl;aralkyls such as benzyl, naphthylmethyl, and phenethyl; aryloxys such asphenoxy and tolyloxy; arylalkoxys such as benzyloxy and phenethyloxy;aromatic hydrocarbon groups or condensed polycyclic aromatic groups suchas phenyl, biphenylyl, terphenylyl, naphthyl, anthracenyl, phenanthryl,fluorenyl, indenyl, pyrenyl, perylenyl, fluoranthenyl, andtriphenylenyl; aromatic heterocyclic groups such as pyridyl, furanyl,pyranyl, thienyl, furyl, pyrrolyl, thienyl, quinolyl, isoquinolyl,benzofuranyl, benzothienyl, indolyl, carbazolyl, benzooxazolyl,benzothiazolyl, quinoxalyl, benzoimidazolyl, pyrazolyl, dibenzofuranyl,dibenzothienyl, and carbolinyl; arylvinyls such as styryl andnaphthylvinyl; acyls such as acetyl and benzoyl; dialkylamino groupssuch as dimethylamino and diethylamino; disubstituted amino groups suchas diphenylamino and dinaphthylamino, substituted with aromatichydrocarbon groups or condensed polycyclic aromatic groups;diaralkylamino groups such as dibenzylamino and diphenethylamino;disubstituted amino groups such as dipyridylamino and dithienylamino,substituted with aromatic heterocyclic groups; dialkenylamino groupssuch as diallylamino; and disubstituted amino groups substituted with asubstituent selected from alkyl, an aromatic hydrocarbon group, acondensed polycyclic aromatic group, aralkyl, an aromatic heterocyclicgroup, and alkenyl. These substituents may be further substituted. Thesesubstituents may bind to each other via a single bond, substituted orunsubstituted methylene, an oxygen atom, or a sulfur atom to form aring.

Specific examples of the “aryloxy” in the “substituted or unsubstitutedaryloxy” represented by R1 to R18 in general formulae (1) to (4) can bephenoxy, tolyloxy, biphenylyloxy, terphenylyloxy, naphthyloxy,anthryloxy, phenanthryloxy, fluorenyloxy, indenyloxy, pyrenyloxy, andperylenyloxy. These groups may bind to each other via a single bond,substituted or unsubstituted methylene, an oxygen atom, or a sulfur atomto form a ring.

Specific examples of the “substituent” in the “substituted aryloxy”represented by R1 to R18 in general formulae (1) to (4) can be adeuterium atom; trifluoromethyl; cyano; nitro; halogen atoms such as afluorine atom, a chlorine atom, a bromine atom, and an iodine atom;linear or branched alkyls of 1 to 6 carbon atoms such as methyl, ethyl,n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl,neopentyl, and n-hexyl; linear or branched alkoxys of 1 to 6 carbonatoms such as methoxy, ethoxy, and propyloxy; alkenyls such as allyl;aralkyls such as benzyl, naphthylmethyl, and phenethyl; aryloxys such asphenoxy and tolyloxy; arylalkoxys such as benzyloxy and phenethyloxy;aromatic hydrocarbon groups or condensed polycyclic aromatic groups suchas phenyl, biphenylyl, terphenylyl, naphthyl, anthracenyl, phenanthryl,fluorenyl, indenyl, pyrenyl, perylenyl, fluoranthenyl, andtriphenylenyl; aromatic heterocyclic groups such as pyridyl, furanyl,pyranyl, thienyl, furyl, pyrrolyl, thienyl, quinolyl, isoquinolyl,benzofuranyl, benzothienyl, indolyl, carbazolyl, benzooxazolyl,benzothiazolyl, quinoxalyl, benzoimidazolyl, pyrazolyl, dibenzofuranyl,dibenzothienyl, and carbolinyl; arylvinyls such as styryl andnaphthylvinyl; acyls such as acetyl and benzoyl; dialkylamino groupssuch as dimethylamino and diethylamino; disubstituted amino groups suchas diphenylamino and dinaphthylamino, substituted with aromatichydrocarbon groups or condensed polycyclic aromatic groups;diaralkylamino groups such as dibenzylamino and diphenethylamino;disubstituted amino groups such as dipyridylamino and dithienylamino,substituted with aromatic heterocyclic groups; dialkenylamino groupssuch as dialkylamino; and disubstituted amino groups substituted with asubstituent selected from alkyl, an aromatic hydrocarbon group, acondensed polycyclic aromatic group, aralkyl, an aromatic heterocyclicgroup, and alkenyl. These substituents may be further substituted. Thesesubstituents may bind to each other via a single bond, substituted orunsubstituted methylene, an oxygen atom, or a sulfur atom to form aring.

Specific examples of the “aromatic hydrocarbon group”, the “aromaticheterocyclic group”, or the “condensed polycyclic aromatic group” in the“substituted or unsubstituted aromatic hydrocarbon group”, the“substituted or unsubstituted aromatic heterocyclic group”, or the“substituted or unsubstituted condensed polycyclic aromatic group”represented by Ar1 to Ar3 in general formulae (1) to (4) can be phenyl,biphenylyl, terphenylyl, naphthyl, anthryl, phenanthryl, fluorenyl,indenyl, pyrenyl, perylenyl, fluoranthenyl, triphenylenyl, pyridyl,furanyl, pyranyl, thienyl, quinolyl, isoquinolyl, benzofuranyl,benzothienyl, indolyl, carbazolyl, benzooxazolyl, benzothiazolyl,quinoxalyl, benzoimidazolyl, pyrazolyl, dibenzofuranyl, dibenzothienyl,and carbolinyl. These groups may directly bind to each other via asingle bond or via substituted or unsubstituted methylene to form aring.

It is preferable that the “aromatic heterocyclic group” in the“substituted or unsubstituted aromatic heterocyclic group” representedby Ar2 to Ar3 in general formulae (1) to (4) is a sulfur-containingaromatic heterocyclic group such as thienyl, benzothienyl,benzothiazolyl, or dibenzothienyl.

Specific examples of the “substituent” in the “substituted aromatichydrocarbon group”, the “substituted aromatic heterocyclic group”, orthe “substituted condensed polycyclic aromatic group” represented by Ar1to Ar3 in general formulae (1) to (4) can be a deuterium atom;trifluoromethyl; cyano; nitro; halogen atoms such as a fluorine atom, achlorine atom, a bromine atom, and an iodine atom; linear or branchedalkyls of 1 to 6 carbon atoms such as methyl, ethyl, n-propyl,isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl,neopentyl, and n-hexyl; linear or branched alkoxys of 1 to 6 carbonatoms such as methoxy, ethoxy, and propyloxy; alkenyls such as allyl;aralkyls such as benzyl, naphthylmethyl, and phenethyl; aryloxys such asphenoxy and tolyloxy; arylalkoxys such as benzyloxy and phenethyloxy;aromatic hydrocarbon groups or condensed polycyclic aromatic groups suchas phenyl, biphenylyl, terphenylyl, naphthyl, anthracenyl, phenanthryl,fluorenyl, indenyl, pyrenyl, perylenyl, fluoranthenyl, andtriphenylenyl; aromatic heterocyclic groups such as pyridyl, furanyl,pyranyl, thienyl, furyl, pyrrolyl, thienyl, quinolyl, isoquinolyl,benzofuranyl, benzothienyl, indolyl, carbazolyl, benzooxazolyl,benzothiazolyl, quinoxalyl, benzoimidazolyl, pyrazolyl, dibenzofuranyl,dibenzothienyl, and carbolinyl; arylvinyls such as styryl andnaphthylvinyl; acyls such as acetyl and benzoyl; dialkylamino groupssuch as dimethylamino and diethylamino; disubstituted amino groups suchas diphenylamino and dinaphthylamino, substituted with aromatichydrocarbon groups or condensed polycyclic aromatic groups;diaralkylamino groups such as dibenzylamino and diphenethylamino;disubstituted amino groups such as dipyridylamino and dithienylamino,substituted with aromatic heterocyclic groups; dialkenylamino groupssuch as diallylamino; and disubstituted amino groups substituted with asubstituent selected from alkyl, an aromatic hydrocarbon group, acondensed polycyclic aromatic group, aralkyl, an aromatic heterocyclicgroup, and alkenyl. These substituents may be further substituted. Thesesubstituents may bind to each other or bind to the “substituted aromatichydrocarbon group”, the “substituted aromatic heterocyclic group”, orthe “substituted condensed polycyclic aromatic group” represented by Ar1to Ar3, via a single bond, substituted or unsubstituted methylene, anoxygen atom, or a sulfur atom to form a ring.

Specific examples of the “divalent group of an aromatic hydrocarbon”,the “divalent group of an aromatic heterocyclic ring”, or the “divalentgroup of condensed polycyclic aromatics” in the “divalent group of asubstituted or unsubstituted aromatic hydrocarbon”, the “divalent groupof a substituted or unsubstituted aromatic heterocyclic ring”, or the“divalent group of substituted Or unsubstituted condensed polycyclicaromatics” represented by A in general formulae (1), (2), and (4) can bephenylene, biphenylene, terphenylene, tetrakisphenylene, naphthylene,anthrylene, phenanthrylene, fluorenylene, phenanthrolylene, indenylene,pyrenylene, perylenylene, fluoranthenylene, triphenylenylene,pyridinylene, pyrimidinylene, quinolylene, isoquinolylene, indolylene,carbazolylene, quinoxalylene, benzoimidazolylene, pyrazolylene,naphthyridinylene, phenanthrolinylene, acridinylene, thienylene,benzothienylene, benzothiazolylene, and dibenzothienylene.

It is preferable that the “divalent group of an aromatic heterocyclicring” in the “divalent group of a substituted or unsubstituted aromaticheterocyclic ring” represented by A in general formulae (1), (2), and(4) is a divalent group of a sulfur-containing aromatic heterocyclicring such as thienylene, benzothienylene, benzothiazolylene, ordibenzothienylene.

Specific examples of the “substituent” in the “divalent group of asubstituted aromatic hydrocarbon”, the “divalent group of a substitutedaromatic heterocyclic ring”, or the “divalent group of substitutedcondensed polycyclic aromatics” represented by A in general formulae(1), (2), and (4) can be a deuterium atom; trifluoromethyl; cyano;nitro; halogen atoms such as a fluorine atom, a chlorine atom, a bromineatom, and an iodine atom; linear or branched alkyls of 1 to 6 carbonatoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl,tert-butyl, n-pentyl, isopentyl, neopentyl, and n-hexyl; linear orbranched alkoxys of 1 to 6 carbon atoms such as methoxy, ethoxy, andpropyloxy; alkenyls such as allyl; aralkyls such as benzyl,naphthylmethyl, and phenethyl; aryloxys such as phenoxy and tolyloxy;arylalkoxys such as benzyloxy and phenethyloxy; aromatic hydrocarbongroups or condensed polycyclic aromatic groups such as phenyl,biphenylyl, terphenylyl, naphthyl, anthracenyl, phenanthryl, fluorenyl,indenyl, pyrenyl, perylenyl, fluoranthenyl, and triphenylenyl; aromaticheterocyclic groups such as pyridyl, furanyl, pyranyl, thienyl, furyl,pyrrolyl, thienyl, quinolyl, isoquinolyl, benzofuranyl, benzothienyl,indolyl, carbazolyl, benzooxazolyl, benzothiazolyl, quinoxalyl,benzoimidazolyl, pyrazolyl, dibenzofuranyl, dibenzothienyl, andcarbolinyl; arylvinyls such as styryl and naphthylvinyl; and acyls suchas acetyl and benzoyl. These substituents may be further substituted.These substituents may bind to each other via a single bond, substitutedor unsubstituted methylene, an oxygen atom, or a sulfur atom to form aring.

Among the compounds of the general formula (4) having an acridan ringstructure, the compounds of the following general formula (4′), (4″),(4′″), or (4″″) having an acridan ring structure are preferably used foran organic EL device.

In the formula, Ar2 and Ar3 may be the same or different, and representa substituted or unsubstituted aromatic hydrocarbon group, a substitutedor unsubstituted aromatic heterocyclic group, or a substituted orunsubstituted condensed polycyclic aromatic group. Ar2 and Ar3 maydirectly bind to each other via a single bond or via substituted orunsubstituted methylene, an oxygen atom, or a sulfur atom to form aring, and substituents of Ar2 and Ar3 may bind to each other via asingle bond, substituted or unsubstituted methylene, an oxygen atom, ora sulfur atom to form a ring. R1 to R7, R10 to R13, R14, R15, R17, andR18 may be the same or different, and represent a hydrogen atom, adeuterium atom, a fluorine atom, a chlorine atom, cyano,trifluoromethyl, nitro, linear or branched alkyl of 1 to 6 carbon atomsthat may have a substituent, cycloalkyl of 5 to 10 carbon atoms that mayhave a substituent, linear or branched alkenyl of 2 to 6 carbon atomsthat may have a substituent, linear or branched alkyloxy of 1 to 6carbon atoms that may have a substituent, cycloalkyloxy of 5 to 10carbon atoms that may have a substituent, a substituted or unsubstitutedaromatic hydrocarbon group, a substituted or unsubstituted aromaticheterocyclic group, a substituted or unsubstituted condensed polycyclicaromatic group, or substituted or unsubstituted aryloxy, wherein R1 andR2, R2 and R3, R3 and R4, R6 and R7, R10 and R11, R12 and R13, R14 andR15, and R17 and R18 may bind to each other via a single bond,substituted or unsubstituted methylene, an oxygen atom, or a sulfur atomto form a ring. R8 and R9 may be the same or different, and representtrifluoromethyl, linear or branched alkyl of 1 to 6 carbon atoms thatmay have a substituent, cycloalkyl of 5 to 10 carbon atoms that may havea substituent, linear or branched alkenyl of 2 to 6 carbon atoms thatmay have a substituent, linear or branched alkyloxy of 1 to 6 carbonatoms that may have a substituent, cycloalkyloxy of 5 to 10 carbon atomsthat may have a substituent, a substituted or unsubstituted aromatichydrocarbon group, a substituted or unsubstituted aromatic heterocyclicgroup, a substituted or unsubstituted condensed polycyclic aromaticgroup, or substituted or unsubstituted aryloxy, which may bind to eachother via a single bond, substituted or unsubstituted methylene, anoxygen atom, or a sulfur atom to form a ring.

In the formula, Ar2 and Ar3 may be the same or different, and representa substituted or unsubstituted aromatic hydrocarbon group, a substitutedor unsubstituted aromatic heterocyclic group, or a substituted orunsubstituted condensed polycyclic aromatic group. Ar2 and Ar3 maydirectly bind to each other via a single bond or via substituted orunsubstituted methylene, an oxygen atom, or a sulfur atom to form aring, and substituents of Ar2 and Ar3 may bind to each other via asingle bond, substituted or unsubstituted methylene, an oxygen atom, ora sulfur atom to form a ring. R1 to R7, and R10 to R13 may be the sameor different, and represent a hydrogen atom, a deuterium atom, afluorine atom, a chlorine atom, cyano, trifluoromethyl, nitro, linear orbranched alkyl of 1 to 6 carbon atoms that may have a substituent,cycloalkyl of 5 to 10 carbon atoms that may have a substituent, linearor branched alkenyl, of 2 to 6 carbon atoms that may have a substituent,linear or branched alkyloxy of 1 to 6 carbon atoms that may have asubstituent, cycloalkyloxy of 5 to 10 carbon atoms that may have asubstituent, a substituted or unsubstituted aromatic hydrocarbon group,a substituted or unsubstituted aromatic heterocyclic group, asubstituted or unsubstituted condensed polycyclic aromatic group, orsubstituted or unsubstituted aryloxy, wherein R1 and R2, R2 and R3, R3and R4, R6 and R7, R10 and R11, and R12 and R13 may bind to each othervia a single bond, substituted or unsubstituted methylene, an oxygenatom, or a sulfur atom to form a ring. R8 and R9 may be the same ordifferent, and represent trifluoromethyl, linear or branched alkyl of 1to 6 carbon atoms that may have a substituent, cycloalkyl of 5 to 10carbon atoms that may have a substituent, linear or branched alkenyl of2 to 6 carbon atoms that may have a substituent, linear or branchedalkyloxy of 1 to 6 carbon atoms that may have a substituent,cycloalkyloxy of 5 to 10 carbon atoms that may have a substituent, asubstituted or unsubstituted aromatic hydrocarbon group, a substitutedor unsubstituted aromatic heterocyclic group, a substituted orunsubstituted condensed polycyclic aromatic group, or substituted orunsubstituted aryloxy, which may bind to each other via a single bond,substituted or unsubstituted methylene, an oxygen atom, or a sulfur atomto form a ring.

In the formula, Ar2 and Ar3 may be the same or different, and representa substituted or unsubstituted aromatic hydrocarbon group, a substitutedor unsubstituted aromatic heterocyclic group, or a substituted orunsubstituted condensed polycyclic aromatic group. Ar2 and Ar3 maydirectly bind to each other via a single bond or via substituted orunsubstituted methylene, an oxygen atom, or a sulfur atom to form aring, and substituents of Ar2 and Ar3 may bind to each other via asingle bond, substituted or unsubstituted methylene, an oxygen atom, ora sulfur atom to form a ring. R1, R2, R4 to R7, R10 to R13, and R14 toR18 may be the same or different, and represent a hydrogen atom, adeuterium atom, a fluorine atom, a chlorine atom, cyano,trifluoromethyl, nitro, linear or branched alkyl of 1 to 6 carbon atomsthat may have a substituent, cycloalkyl of 5 to 10 carbon atoms that mayhave a substituent, linear or branched alkenyl of 2 to 6 carbon atomsthat may have a substituent, linear or branched alkyloxy of 1 to 6carbon atoms that may have a substituent, cycloalkyloxy of 5 to 10carbon atoms that may have a substituent, a substituted or unsubstitutedaromatic hydrocarbon group, a substituted or unsubstituted aromaticheterocyclic group, a substituted or unsubstituted condensed polycyclicaromatic group, or substituted or unsubstituted aryloxy, wherein R1 andR2, R6 and R7, R10 and R11, R12 and R13, R14 and R15, R15 and R16, R16and R17, and R17 and R18 may bind to each other via a single bond,substituted or unsubstituted methylene, an oxygen atom, or a sulfur atomto form a ring. R8 and R9 may be the same or different, and representtrifluoromethyl, linear or branched alkyl of 1 to 6 carbon atoms thatmay have a substituent, cycloalkyl of 5 to 10 carbon atoms that may havea substituent, linear or branched alkenyl of 2 to 6 carbon atoms thatmay have a substituent, linear or branched alkyloxy of 1 to 6 carbonatoms that may have a substituent, cycloalkyloxy of 5 to 10 carbon atomsthat may have a substituent, a substituted or unsubstituted aromatichydrocarbon group, a substituted or unsubstituted aromatic heterocyclicgroup, a substituted or unsubstituted condensed polycyclic aromaticgroup, or substituted or unsubstituted aryloxy, which may bind to eachother via a single bond, substituted or unsubstituted methylene, anoxygen atom, or a, sulfur atom to form a ring.

In the formula, Ar2 and Ar3 may be the same or different, and representa substituted or unsubstituted aromatic hydrocarbon group, a substitutedor unsubstituted aromatic heterocyclic group, or a substituted orunsubstituted condensed polycyclic aromatic group. Ar2 and Ar3 maydirectly bind to each other via a single bond or via substituted orunsubstituted methylene, an oxygen atom, or a sulfur atom to form aring, and substituents of Ar2 and Ar3 may bind to each other via asingle bond, substituted or unsubstituted methylene, an oxygen atom, ora sulfur atom to form a ring. R1, R2, R4 to R7, R10 to R13, R14, R15,R17, and R18 may be the same or different, and represent a hydrogenatom, a deuterium atom, a fluorine atom, a chlorine atom, cyano,trifluoromethyl, nitro, linear or branched alkyl of 1 to 6 carbon atomsthat may have a substituent, cycloalkyl of 5 to 10 carbon atoms that mayhave a substituent, linear or branched alkenyl of 2 to 6 carbon atomsthat may have a substituent, linear or branched alkyloxy of 1 to 6carbon atoms that may have a substituent, cycloalkyloxy of 5 to 10carbon atoms that may have a substituent, a substituted or unsubstitutedaromatic hydrocarbon group, a substituted or unsubstituted aromaticheterocyclic group, a substituted or unsubstituted condensed polycyclicaromatic group, or substituted or unsubstituted aryloxy, wherein R1 andR2, R6 and R7, R10 and R11, R12 and R13, R14 and R15, and R17 and R18may bind each other via a single bond, substituted or unsubstitutedmethylene, an oxygen atom, or, a sulfur atom to form a ring. R8 and R9may be the same or different, and represent trifluoromethyl, linear orbranched alkyl of 1 to 6 carbon atoms that may have a substituent,cycloalkyl of 5 to 10 carbon atoms that may have a substituent, linearor branched alkenyl of 2 to 6 carbon atoms that may have a substituent,linear or branched alkyloxy of 1 to 6 carbon atoms that may have asubstituent, cycloalkyloxy of 5 to 10 carbon atoms that may have asubstituent, a substituted or unsubstituted aromatic hydrocarbon group;a substituted or unsubstituted aromatic heterocyclic group, asubstituted or unsubstituted condensed polycyclic aromatic group, orsubstituted or unsubstituted aryloxy, which may bind to each other via asingle bond, substituted or unsubstituted methylene, an oxygen atom, ora sulfur atom to form a ring.

The compounds of general formulae (1) to (4) having an acridan ringstructure of the present invention are novel compounds and have superiorelectron blocking ability, superior amorphousness and a more stablethin-film state compared to conventional hole transport materials.

The compounds of general formulae (1) to (4) having an acridan ringstructure of the present invention can be used as a constituent materialof the hole injection layer and/or hole transport layer of an organicelectroluminescent device (hereinafter referred to as an organic ELdevice). With the use of material having higher hole injectability,higher mobility, higher electron blocking performance and higherstability to electrons than conventional materials, excitons generatedin a light emitting layer can be confined, and the probability ofhole-electron recombination can be improved. This improves luminousefficiency, lowers driving voltage and thus improves the durability ofthe organic EL device.

The compounds of general formulae (1) to (4) having an acridan ringstructure of the present invention can also be used as a constituentmaterial of the electron blocking layer of an organic EL device. Withthe use of material having an excellent electron blocking ability andhaving superior hole transportability and higher stability in athin-film state than conventional materials, driving voltage is loweredand current resistance is improved while maintaining high luminousefficiency. As a result, the maximum emission luminance of the organicEL device is improved.

The compounds of general formulae (1) to (4) having an acridan ringstructure of the present invention can also be used as a constituentmaterial of the light emitting layer of the organic EL device. Thematerial of the present invention having superior hole transportabilityand a wider band gap than conventional materials is used as the hostmaterial of the light emitting layer in order to form the light emittinglayer by carrying a fluorescent material or phosphorescent materialcalled a dopant. In this way, the organic EL device with a low drivingvoltage and improved luminous efficiency can be achieved.

The high efficiency and high durability of the organic EL device in thepresent invention can be achieved because of the use of the compoundhaving an acridan ring structure, which has greater hole mobility,superior electron blocking ability and superior amorphousness thanconventional hole transport materials as well as a stable thin-filmstate.

Effects of the Invention

The compound having an acridan ring structure of the present inventionis useful as the constituent material of the hole injection layer, holetransport layer, electron blocking layer, or light emitting layer of theorganic EL device. The compound has an excellent electron blockingability and satisfactory amorphousness, and excels in heat resistance aswell as a stable thin-film state. The organic EL device of the presentinvention has high luminous efficiency and high power efficiency, andthe actual driving voltage of the device can thereby be lowered.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a 1H-NMR chart of the compound of Example 1 of the presentinvention (Compound II).

FIG. 2 is a 1H-NMR chart of the compound of Example 2 of the presentinvention (Compound 19).

FIG. 3 is a 1H-NMR chart of the compound of Example 3 of the presentinvention (Compound 27).

FIG. 4 is a 1H-NMR chart of the compound of Example 4 of the presentinvention (Compound 12).

FIG. 5 is a 1H-NMR chart of the compound of Example 5 of the presentinvention (Compound 13).

FIG. 6 is a 1H-NMR chart of the compound of Example 6 of the presentinvention (Compound 24).

FIG. 7 is a 1H-NMR chart of the compound of Example 7 of the presentinvention (Compound 23).

FIG. 8 is a diagram illustrating the configuration of the EL devices ofExamples 10 and 11 and Comparative Example 1.

MODE FOR CARRYING OUT THE INVENTION

The compounds having an acridan ring structure of the present inventionare novel compounds, and may be synthesized, for example, as follows.First, 2-bromo-10-arylacridan is synthesized by bromination of acridansubstituted with an aryl group at the corresponding tenth position,using bromine, N-bromosuccinimide, or the like (refer to Patent Document3, for example). Boronic acid or borate synthesized by the reaction ofthe resulting bromo compound with compounds such as pinacolborane andbis(pinacolato)diboron (refer to Non-Patent Document 4, for example) canthen be reacted with aryl halides substituted with various diarylaminogroups in a cross-coupling reaction such as Suzuki coupling (refer toNon-Patent Document 5, for example) to synthesize the compounds havingan acridan ring structure.

The compounds having an acridan ring structure of the present inventionmay be synthesized also by using the following method. First, acridansubstituted with an arylamino group at the corresponding second positioncan be reacted with various aryl halides in a cross-coupling reactionsuch as Ullmann coupling (refer to Non-Patent Document 6, for example),and the compounds having an acridan ring structure can then besynthesized.

The following presents specific examples of preferred compounds amongthe compounds of general formula (1) having an acridan ring structure.The present invention, however, is not restricted to these compounds.

These compounds were purified by methods such as column chromatography,adsorption using, for example, silica gel, activated carbon, oractivated clay, and recrystallization or crystallization using asolvent. The compounds were identified by an NMR analysis. A glasstransition point (Tg), a melting point, and a work function weremeasured as material property values. The glass transition point (Tg)can be used as an index of stability in the thin-film state, the meltingpoint as an index of vapor deposition, and the work function as an indexof hole transportability.

The glass transition point (Tg) and the melting point were measured by ahigh-sensitive differential scanning calorimeter (DSC3100S produced byBruker AXS) using powder.

For the measurement of the work function, a 100 nm-thick thin film wasfabricated on an ITO substrate, and an atmosphere photoelectronspectrometer (AC-3 produced by Riken Keiki Co., Ltd.) was used.

The organic EL device of the present invention may have a structureincluding an anode, a hole transport layer, an electron blocking layer,a light emitting layer, an electron transport layer, and a cathodesuccessively formed on a substrate, optionally with a hole injectionlayer between the anode and the hole transport layer, or with anelectron injection layer between the electron transport layer and thecathode. In such multilayer structures, some of the organic layers maybe omitted. For example, the device May be configured to include ananode, a hole transport layer, a light emitting layer, an electrontransport layer, and a cathode successively formed on a substrate.

Electrode materials with high work functions such as ITO and gold areused as the anode of the organic EL device of the present invention. Thehole injection layer of the organic EL device of the present inventionmay be made of material such as porphyrin compounds as represented bycopper phthalocyanine, starburst-type triphenylamine derivatives,various triphenylamine tetramers, accepting heterocyclic compounds suchas hexacyano azatriphenylene, and coating-type polymer materials, inaddition to the compounds of general formula (1) having an acridan ringstructure of the present invention. These materials may be formed into athin film by a vapor deposition method or other known methods such as aspin coating method and an inkjet method.

Examples of material used for the hole transport layer of the organic ELdevice of the present invention can be benzidine derivatives such asN,N′-diphenyl-N,N′-di(m-tolyl)benzidine (hereinafter referred to asTPD), N,N′-diphenyl-N,N′-di(a-naphthyl)benzidine (hereinafter referredto as NPD), and N,N,N′,N′-tetrabiphenylylbenzidine;1,1-bis[4-(di-4-tolylamino)phenyl]cyclohexane (hereinafter referred toas TAPC); and various triphenylamine trimers and tetramers, in additionto the compounds of general formula (1) having an acridan ring structureof the present invention. These may be individually deposited for filmforming, may be used as a single layer deposited mixed with othermaterials, or may be formed as a laminate of individually depositedlayers, a laminate of mixedly deposited layers, or a laminate of theindividually deposited layer and the mixedly deposited layer. Examplesof material used for the hole injection/transport layer can becoating-type polymer materials such as poly(3,4-ethylenedioxythiophene)(hereinafter referred to as PEDOT)/poly(styrene sulfonate) (hereinafterreferred to as PSS). These materials may be formed into, a thin-film bya vapor deposition method or other known methods such as a spin coatingmethod and an inkjet method.

Further, material used for the hole injection layer or the holetransport layer may be obtained by p-doping trisbromophenylaminehexachloroantimony or the like into the material commonly used for theselayers, or may be, for example, polymer compounds each having a TPDstructure as a part of the compound structure.

Examples of material used for the electron blocking layer of the organicEL device of the present invention can be compounds having an electronblocking effect, including, for example, carbazole derivatives such as4,4′,4″-tri(N-carbazolyl)triphenylamine (hereinafter referred to asTCTA), 9,9-bis[4-(carbazol-9-yl)phenyl]fluorene,1,3-bis(carbazol-9-yl)benzene (hereinafter referred to as mCP), and2,2-bis(4-carbazol-9-ylphenyl)adamantane (hereinafter referred to asAd-Cz); and compounds having a triphenylsilyl group and a triarylaminestructure, as represented by9-[4-(carbazol-9-yl)phenyl]-9-[4-(triphenylsilyl)phenyl]-9H-fluorene, inaddition to the compounds of general formula (1) having an acridan ringstructure of the present invention. These may be individually depositedfor film forming, may be used as a single layer deposited mixed withother materials, or may be formed as a laminate of individuallydeposited layers, a laminate of mixedly deposited layers, or a laminateof the individually deposited layer and the mixedly deposited layer.These materials may be formed into a thin-film by using a vapordeposition method or other known methods such as a spin coating methodand an inkjet method.

Examples of material used for the light emitting layer of the organic ELdevice of the present invention can be various metal complexes,anthracene derivatives, bis(styryl)benzene derivatives, pyrenederivatives, oxazole derivatives, and polyparaphenylene vinylenederivatives, in addition to quinolinol derivative metal complexes suchas Alq₃. Further, the light emitting layer may comprise a host materialand a dopant material. Examples of the host material can be thiazolederivatives, benzimidazole derivatives, and polydialkyl fluorenederivatives, in addition to the above light-emitting materials and thecompounds of general formula (1) having an acridan ring structure of thepresent invention. Examples of the dopant material can be quinacridone,coumarin, rubrene, perylene, derivatives thereof, benzopyranderivatives, rhodamine derivatives, and aminostyryl derivatives. Thesemay be individually deposited for film forming, may be used as a singlelayer deposited mixed with other materials, or may be formed as alaminate of individually deposited layers, a laminate of mixedlydeposited layers, or a laminate of the individually deposited layer andthe mixedly deposited layer.

Further, the light-emitting material may be a phosphorescentlight-emitting material. Phosphorescent materials as metal complexes ofmetals such as iridium and platinum may be used as the phosphorescentlight-emitting material. Examples of the phosphorescent materials can begreen phosphorescent materials, such as Ir(ppy)₃, blue phosphorescentmaterials such as FIrpic and FIr₆, and red phosphorescent materials suchas Btp₂Ir(acac). As the hole injecting and transporting host material,the compounds of general formula (1) having an acridan ring structure ofthe present invention may be used in addition to carbazole derivativessuch as 4,4′-di (N-carbazolyl)biphenyl (hereinafter referred to as CBP),TCTA, and mCP. Compounds such as p-bis(triphenylsilyl)benzene(hereinafter referred to as UGH2) and2,2′,2″-(1,3,5-phenylene)-tris(1-phenyl-1H-benzimidazole) (hereinafterreferred to as TPBI) may be used as the electron transporting hostmaterial to produce a high-performance organic EL device.

In order to avoid concentration quenching, it is preferable to dope thehost material with the phosphorescent light-emitting material byco-evaporation in a range of 1 to 30 weight percent to the whole lightemitting layer.

These materials may be formed into a thin-film by using a vapordeposition method or other known methods such as a spin coating methodand an inkjet method.

The hole blocking layer of the organic EL device of the presentinvention may be formed by using hole blocking compounds such as variousrare earth complexes, triazole derivatives, triazine derivatives, andoxadiazole derivatives, in addition to the metal complexes ofphenanthroline derivatives such as bathocuproin (hereinafter referred toas BCP), and the metal complexes of quinolinol derivatives such asaluminum(III) bis(2-methyl-8-quinolinate)-4-phenylphenolate (hereinafterreferred to as BAlq). These materials may also serve as the material ofthe electron transport layer. These may be individually deposited forfilm forming, may be used as a single layer deposited mixed with othermaterials, or may be formed as a laminate of individually depositedlayers, a laminate of mixedly deposited layers, or laminate of theindividually deposited layer and the mixedly deposited layer. Thesematerials may be formed into a thin-film by using a vapor depositionmethod or other known methods such as a spin coating method and aninkjet method.

Examples of material used for the electron transport layer of theorganic EL device of the present invention can be various metalcomplexes, triazole derivatives, triazine derivatives, oxadiazolederivatives, thiadiazole derivatives, carbodiimide derivatives,quinoxaline derivatives, phenanthroline derivatives, and silolederivatives, in addition to the metal complexes of quinolinolderivatives such as Alq₃ and BAlq. These may be individually depositedfor film forming, may be used as a single layer deposited mixed withother materials, or may be formed as a laminate of individuallydeposited layers, a laminate of mixedly deposited layers, or a laminateof the individually deposited layer and the mixedly deposited layer.These materials may be formed into a thin-film by using a vapordeposition method or other known methods such as a spin coating methodand an inkjet method.

Examples of material used for the electron injection layer of theorganic EL device of the present invention can be alkali metal saltssuch as lithium fluoride and cesium fluoride; alkaline earth metal saltssuch as magnesium fluoride; and metal oxides such as aluminum oxide.However, the electron injection layer may be omitted in the preferredselection of the electron transport layer and the cathode.

The cathode of the organic EL device of the present invention may bemade of an electrode material with a low work function such as aluminum,or an alloy of an electrode material with an even lower work functionsuch as a magnesium-silver alloy, a magnesium-indium alloy, or analuminum-magnesium alloy.

The following describes an embodiment of the present invention in moredetail based on Examples. The present invention, however, is notrestricted to the following Examples.

EXAMPLE 1 Synthesis of[4-(9,9-dimethyl-7,10-diphenylacridan-2-yl)phenyl]-diphenylamine(Compound 11)

2-Bromo-9,9-dimethyl-7,10-diphenylacridan (2.54 g),4-(diphenylamino)phenylboronic acid (1.75 g), toluene (25 ml), ethanol(2 ml), and a 2M potassium carbonate aqueous solution (9 ml) were addedto a reaction vessel in a nitrogen atmosphere and aerated with nitrogengas for 30 min under ultrasonic irradiation. The mixture was heatedafter adding tetrakis(triphenylphosphine)palladium (0.20 g) and stirredat 68° C. for 8 hours. The mixture was allowed to cool to a roomtemperature, and an organic layer was collected by a liquid separatingoperation. The organic layer was dried with magnesium sulfate andconcentrated under reduced pressure to obtain a yellow amorphous crudeproduct. The crude product was recrystallized with n-hexane, dissolvedby adding toluene (30 ml), and purified by adsorption using silica gel(1.17 g Methanol (20 ml) was added to this solution to precipitatecrystals, and the crystals were further purified by recrystallizationusing toluene/methanol to obtain a white powder of[4-(9,9-dimethyl-7,10-diphenylacridan-2-yl)phenyl]-diphenylamine (1.9 g;yield 54%).

The structure of the resulting white powder was identified by NMR. The¹H-NMR measurement result is presented in FIG. 1.

1H-NMR (THF-d₈) detected 36 hydrogen signals, as follows. δ (ppm)=7.75(2H), 7.68 (2H), 7.56-7.54 (3H), 7.47 (2H), 7.40 (2H), 7.35 (2H),7.24-7.18 (7H), 7.09-7.07 (6H), 6.97 (2H), 6.33-6.30 (2H), 1.80 (6H).

EXAMPLE 2 Synthesis of{4-[10-(9,9-dimethyl-9H-fluorene-2-yl)-9,9-dimethylacridan-2-yl]phenyl}-diphenylamine(Compound 19)

[4-(9,9-Dimethylacridan-2-yl)phenyl]-diphenylamine (2.02 g),2-bromo-9,9-dimethyl-9H-fluorene (1.37 g), a copper powder (0.036 g),potassium carbonate (0.94 g), sodium bisulfite (0.078 g), and dodecane(4 ml) were added to a nitrogen-substituted reaction vessel and stirredat 200° C. for 35 hours. The mixture was allowed to cool to a roomtemperature, and toluene (30 ml) and methanol (30 ml) were added.Precipitated insoluble matter was removed by filtration and concentratedunder reduced pressure to obtain a black crude product. The crudeproduct was purified by column chromatography (carrier: silica gel;eluent: hexane/toluene), crystallized with diisopropyl ether/methanol,and then crystallized with ethyl acetate/diisopropyl ether/hexane toobtain a pale yellowish white powder of{4-[10-(9,9-dimethyl-9H-fluorene-2-yl)-9,9-dimethylacridan-2-yl]phenyl}-diphenylamine(0.96 g; yield 33%).

The structure of the resulting pale yellowish white powder wasidentified by NMR. The ¹H-NMR measurement result is presented in FIG. 2.

1H-NMR (THF-d₈) detected 40 hydrogen signals, as follows. δ (ppm)=8.04(1H), 7.85 (1H), 7.72 (1H), 7.52-7.46 (5H), 7.36-7.30 (3H), 7.23-7.21(4H), 7.17 (1H), 7.08-7.07 (6H), 6.97 (2H), 6.90-6.87 (2H), 6.38 (1H),6.34 (1H), 1.73 (6H), 1.53 (6H).

EXAMPLE 3 Synthesis of[4-(9,9-dimethyl-7,10-diphenylacridan-2-yl)phenyl]-(9,9-dimethyl-9H-fluorene-2-yl)-phenylamine(Compound 27)

9,9-Dimethyl-2,10-diphenyl-7-(4,4,5,5-tetramethyl-[1,3,2]dioxaboran-2-yl)acridan(2.02 g), (4-bromophenyl)-(9,9-dimethyl-9H-fluorene-2-yl)-phenylamine(1.90 g), toluene (20 ml), ethanol (2 ml), and a 2M potassium carbonateaqueous solution (6 ml) were added to a nitrogen-substituted reactionvessel and aerated with nitrogen gas for 30 min under ultrasonicirradiation. The mixture was heated after addingtetrakis(triphenylphosphine)palladium (0.14 g) and stirred at 72° C. for8.5 hours. The mixture was allowed to cool to a room temperature, and anorganic layer was collected by a liquid separating operation. Theorganic layer was dried with magnesium sulfate and concentrated underreduced pressure to obtain a brown crude product. The crude product waspurified by column chromatography (carrier: silica gel; eluent:hexane/toluene) and crystallized with acetone/methanol to obtain a whitepowder of[4-(9,9-dimethyl-7,10-diphenylacridan-2-yl)phenyl]-(9,9-dimethyl-9H-fluorene-2-yl)-phenylamine(1.98 g; yield 64%).

The structure of the resulting white powder was identified by NMR. The1H-NMR measurement result is presented in FIG. 3.

1H-NMR (THF-d₈) detected 44 hydrogen signals, as follows. δ (ppm)=7.76(2H), 7.68-7.62 (4H), 7.56-7.55 (3H), 7.49 (2H), 7.41-7.35 (5H),7.29-7.20 (8H), 7.13-7.12 (4H), 7.03 (1H), 6.98 (1H), 6.31 (2H), 1.80(6H), 1.40 (6H).

EXAMPLE 4 Synthesis of(biphenyl-4-yl)-[4-(9,9-dimethyl-7,10-diphenylacridan-2-yl)phenyl]-phenylamine(Compound 12)

2-Bromo-9,9-dimethyl-7,10-diphenylacridan (3.2 g),(biphenyl-4-yl)-[4-(4,4,5,5-tetramethyl-[1,3,2]dioxaboran-2-yl)phenyl]-phenylamine(3.6 g), toluene (40 ml), ethanol (10 ml), and a 2M potassium carbonateaqueous solution (11 ml) were added to a nitrogen-substituted reactionvessel and aerated with nitrogen gas for 30 min under ultrasonicirradiation. The mixture was heated after addingtetrakis(triphenylphosphine)palladium (0.26 g) and stirred at 72° C. for7 hours. The mixture was allowed to cool to a room temperature, andmethanol (50 ml) was added. A precipitated solid was collected byfiltration and washed with water to obtain a red brown crude product.The crude product was dissolved by adding toluene (100 ml) and subjectedto adsorptive purification twice using silica gel (3.7 g). The productwas then crystallized with toluene/methanol to obtain a white powder of(biphenyl-4-yl)-[4-(9,9-dimethyl-7,10-diphenylacridan-2-yl)phenyl]-phenylamine(3.42 g; yield 68%).

The structure of the resulting white powder was identified by NMR. The¹H-NMR measurement result is presented in FIG. 4.

1H-NMR (THF-d₈) detected 40 hydrogen signals, as follows. δ(ppm)=7.77-7.75 (2H), 7.70-7.67 (2H), 7.59-7.50 (9H), 7.41-7.38 (6H),7.25-7.21 (6H), 7.15-7.13 (6H), 7.00 (1H), 6.33-6.31 (2H), 2.48 (6H).

EXAMPLE 5 Synthesis ofbis(biphenyl-4-yl)-[4-(9,9-dimethyl-7,10-diphenylacridan-2-yl)phenyl]amine(Compound 13)

2-Bromo-9,9-dimethyl-7,10-diphenylacridan (2.9 g),bis(biphenyl-4-yl)-[4-(4,4,5,5-tetramethyl-[1,3,2]dioxaboran-2-yl)phenyl]amine(4.0 g), toluene (44 ml), ethanol (11 ml), and a 2M potassium carbonateaqueous solution (8.4 ml) were added to a nitrogen-substituted reactionvessel and aerated with nitrogen gas for 30 min under ultrasonicirradiation. The mixture was heated after addingtetrakis(triphenylphosphine)palladium (0.23 g) and stirred at 72° C. for4.5 hours. The mixture was allowed to cool to a room temperature, and anorganic layer was collected by a liquid separating operation. Theorganic layer was dried with magnesium sulfate and concentrated underreduced pressure to obtain a red crude product. The crude product wasdissolved by adding toluene (75 ml), purified by adsorption using silicagel (5.2 g), and purified by recrystallization using toluene/methanol toobtain a whitish powder ofbis(biphenyl-4-yl)-[4-(9,9-dimethyl-7,10-diphenylacridan-2-yl)phenyl]amine(3.19 g; yield 64%).

The structure of the resulting whitish powder was identified by NMR. The¹H-NMR measurement result is presented in FIG. 5.

1H-NMR (THF-d₈) detected 44 hydrogen signals, as follows. δ (ppm)=7.77(2H), 7.69-7.67 (15H), 7.61-7.53 (8H), 7.41-7.18 (11H), 6.33-6.31 (2H),2.48 (6H).

EXAMPLE 6 Synthesis of(phenyl-4-yl)-[4-{10-(biphenyl-4-yl)-9,9-dimethyl-7-phenylacridan-2-yl}phenyl]-phenylamine(Compound 24)

2-Bromo-10-(biphenyl-4-yl)-9,9-dimethyl-7-phenylacridan (2.7 g),(biphenyl-4-yl)-[4-(4,4,5,5-tetramethyl-[1,3,2]dioxaboran-2-yl)phenyl]-phenylamine(2.8 g), toluene (40 ml), ethanol (10 ml), and a 2M potassium carbonateaqueous solution (8 ml) were added to a nitrogen-substituted reactionvessel and aerated with nitrogen gas for 30 min under ultrasonicirradiation. The mixture was heated after addingtetrakis(triphenylphosphine)palladium (0.13 g) and stirred at 72° C. for3.5 hours. The mixture was allowed to cool to a room temperature, andmethanol (50 ml) was added. A precipitated solid was collected byfiltration and washed with water to obtain an orange crude product. Thecrude product was dissolved by adding toluene (200 ml) and purified byadsorption using silica gel (2.4 g). The product was then crystallizedwith toluene/methanol to obtain a white powder of(phenyl-4-yl)-[4-{10-(biphenyl-4-yl)-9,9-dimethyl-7-phenylacridan-2-yl}phenyl]-phenylamine(3.07 g; yield 78%).

The structure of the resulting white powder was identified by NMR. The¹H-NMR measurement result is presented in FIG. 6.

1H-NMR (THF-d₈) detected 44 hydrogen signals, as follows. δ (ppm)=7.98(2H), 7.78-7.77 (4H), 7.60-7.39 (12H), 7.37-7.35 (5H), 7.27-7.22 (6H),7.16-7.13 (6H), 7.01 (1H), 6.42 (2H), 1.82 (6H).

EXAMPLE 7 Synthesis ofbis(biphenyl-4-yl)-[4-{10-(biphenyl-4-yl)-9,9-dimethyl-7-phenylacridan-2-yl}phenyl]amine(Compound 23)

2-Bromo-10-(biphenyl-4-yl)-9,9-dimethyl-7-phenylacridan (2.5 g),bis(biphenyl-4-yl)-[4-(4,4,5,5-tetramethyl-[1,3,2]dioxaboran-2-yl)phenyl]amine(3.0 g), toluene (37 ml), ethanol (9.3 ml), and a 2M potassium carbonateaqueous solution (7.2 ml) were added to a nitrogen-substituted reactionvessel and aerated with nitrogen gas for 30 min under ultrasonicirradiation. The mixture was heated after addingtetrakis(triphenylphosphine)palladium (0.11 g) and stirred at 72° C. for8.5 hours. The mixture was allowed to cool to a room temperature, andmethanol (40 ml) was added. A precipitated solid was collected byfiltration and washed with water to obtain an orange crude product. Thecrude product was dissolved by adding toluene (360 ml), purified byadsorption using silica gel (3.6 g), and crystallized withtoluene/methanol three times. Further, methanol (60 ml) was added to theproduct, and the product was washed and purified by heating under refluxto obtain a white powder ofbis(biphenyl-4-yl)-[4-{10-(biphenyl-4-yl)-9,9-dimethyl-7-phenylacridan-2-yl}phenyl]amine(3.04 g; yield 75%).

The structure of the resulting white powder was identified by NMR. The1H-NMR Measurement result is presented in FIG. 7.

1H-NMR (THF-d₈) detected 48 hydrogen signals, as follows. δ (ppm)=7.99(2H), 7.79-7.77 (4H), 7.60-7.48 (16H), 7.40-7.35 (7H), 7.28-7.19 (11H),6.42 (2H), 1.82 (6H).

EXAMPLE 8

The melting point and glass transition point of the compounds of thepresent invention were determined using a high-sensitive differentialscanning calorimeter (DSC 3100S produced by Bruker AXS).

Glass Melting transition point point Compound of Example 1 of the 248°C. 106° C. present invention Compound of Example 2 of the 142° C. 115°C. present invention Compound of Example 3 of the 162° C. 129° C.present invention Compound of Example 4 of the 254° C. 118° C. presentinvention Compound of Example 5 of the 258° C. 136° C. present inventionCompound of Example 6 of the 164° C. 130° C. present invention

The compounds of the present invention have glass transition points of100° C. or higher, demonstrating that the compounds of the presentinvention have a stable thin-film state.

EXAMPLE 9

A 100 nm-thick vapor-deposited film was fabricated on an ITO substrateusing the compounds of the present invention, and a work function wasmeasured using an atmosphere photoelectron spectrometer (Model AC-3produced by Riken Keiki Co., Ltd.).

Work function Compound of Example 1 of the present 5.45 eV inventionCompound of Example 2 of the present 5.41 eV invention Compound ofExample 3 of the present 5.45 eV invention Compound of Example 4 of thepresent 5.41 eV invention Compound of Example 5 of the present 5.41 eVinvention Compound of Example 6 of the present 5.49 eV invention

As the results show, the compounds of the present invention havedesirable energy levels compared to the work function 5.4 eV of commonhole transport materials such as NPD and TPD, and thus possess desirablehole transportability.

EXAMPLE 10

An organic EL device, as illustrated in FIG. 8, was fabricated byforming a hole injection layer 3, a hole transport layer 4, a lightemitting layer 5, an electron transport layer 6, an electron injectionlayer 7, and a cathode (an aluminum electrode) 8 in this order by vapordeposition on a glass substrate 1 that had been provided beforehand withan ITO electrode as a transparent anode 2.

Specifically, the glass substrate 1 with ITO formed with a filmthickness of 150 nm thereon was washed with an organic solvent andsubjected to an oxygen plasma treatment to wash the surface. The glasssubstrate with the ITO electrode was then installed in a vacuum vapordeposition apparatus, and the pressure was reduced to 0.001 Pa or less.This was followed by the formation of the hole injection layer 3 byforming Compound 77 of the structural formula below over the transparentanode 2 in a film thickness of 20 nm. The hole transport layer 4 wasthen formed on the hole injection layer 3 by forming the compound ofExample 2 of the present invention (Compound 19) in a film thickness of40 nm. Thereafter, the light emitting layer 5 was formed on the holetransport layer 4 by forming Compounds 78 and 79 of the structuralformulae below in a film thickness of 30 nm using dual vapor depositionat a deposition rate ratio of Compound 78:Compound 79=5:95. Then, theelectron transport layer 6 was formed on the light emitting layer 5 byforming Alq₃ in a film thickness of 30 nm. The electron injection layer7 was then formed on the electron transport layer 6 by forming lithiumfluoride in a film thickness of 0.5 nm. Finally, the cathode 8 wasformed by vapor-depositing aluminum in a film thickness of 150 nm. Thecharacteristics of the organic EL device thus fabricated were measuredin the atmosphere at an ordinary temperature.

Table 1 summarizes the results of the emission characteristicsmeasurements performed by applying a DC voltage to the organic EL deviceproduced by using the compound of Example 2 of the present invention(Compound 19).

EXAMPLE 11

An organic EL device was fabricated under the same conditions used inExample 10, except that the compound of Example 5 of the presentinvention (Compound 13) was formed in a film thickness of 40 nm as thematerial of the hole transport layer 4, instead of using the compound ofExample 2 of the present invention (Compound 19). The characteristics ofthe organic EL device thus fabricated were measured in the atmosphere atan ordinary temperature. Table 1 summarizes the results of the emissioncharacteristics measurements performed by applying a DC voltage to theorganic EL device.

COMPARATIVE EXAMPLE 1

For comparison, an organic EL device was fabricated under the sameconditions used in Example 10, except that Compound 80 of the structuralformula below was formed in a film thickness of 40 nm as the material ofthe hole transport layer 4, instead of using the compound of Example 2of the present invention (Compound 19). The characteristics of theorganic EL device thus fabricated were measured in the atmosphere at anordinary temperature. Table 1 summarizes the results of the emissioncharacteristics measurements performed by applying a DC voltage to theorganic EL device.

TABLE 1 Current Power Voltage Luminance efficiency efficiency [V][cd/m²] [cd/A] [lm/W] (@10 mA/cm²) (@10 mA/cm²) (@10 mA/cm²) (@10mA/cm²) Ex. 10 Compound 19 4.82 960 9.61 6.26 Ex. 11 Compound 13 4.96910 9.10 5.76 Com. Ex. 1 Compound 80 5.17 902 9.03 5.49

As shown in Table 1, the driving voltage when applying a current with acurrent density of 10 mA/cm² was 4.82 V for the compound of Example 2 ofthe present invention (Compound 19) and 4.96 V for the compound ofExample 5 of the present invention (Compound 13), both of which werelower than 5.17 V of Compound 80. The power efficiencies of the compoundof Example 2 in the present invention (Compound 19) and the compound ofExample 5 in the present invention (Compound 13) were 6.26 μm/W and 5.76μm/W respectively, which showed improvement over the power efficiency5.49 μm/W of Compound 80. Further, the compounds of the presentinvention were improved in both of the luminance and the luminousefficiency compared to Compound 80.

As the above results clearly demonstrate, the organic EL devices usingthe compounds having an acridan ring structure in the present inventionhas achieved improvements in luminous efficiency and power efficiency,and a lower actual driving voltage compared to the organic EL deviceusing the Compound 80.

INDUSTRIAL APPLICABILITY

The compounds having an acridan ring structure of the present inventionhave high hole transportability, excel in amorphousness, and have astable thin-film state. The compounds are therefore excellent as thecompounds for organic EL devices. The organic EL devices fabricated withthe compounds can have high luminous efficiency and high powerefficiency and can have a low actual driving voltage to improvedurability. There are potential applications for, for example, homeelectric appliances and illuminations.

Description of Reference Numeral 1 Glass substrate 2 Transparentelectrode 3 Hole injection layer 4 Hole transport layer 5 Light emittinglayer 6 Electron transport layer 7 Electron injection layer 8 Cathode

The invention claimed is:
 1. A compound having an acridan ringstructure, wherein the compound is represented by the following ChemicalFormula (4″),

wherein Ar₂ and Ar₃ may be the same or different, and represent asubstituted or unsubstituted aromatic hydrocarbon group, a substitutedor unsubstituted aromatic heterocyclic group, or a substituted orunsubstituted condensed polycyclic aromatic group, where Ar₂ and Ar₃ maydirectly bind to each other via a single bond or via substituted orunsubstituted methylene, an oxygen atom, or a sulfur atom to form aring, and substituents of Ar₂ and Ar₃ may bind to each other via asingle bond, substituted or unsubstituted methylene, an oxygen atom, ora sulfur atom to form a ring; R₁ to R₇, and R₁₀ to R₁₃ may be the sameor different, and represent a hydrogen atom, a deuterium atom, afluorine atom, a chlorine atom, cyano, trifluoromethyl, nitro, linearalkyl of 1 to 6 carbon atoms that may have a substituent, branched alkylof 3 to 6 carbon atoms that may have a substituent, cycloalkyl of 5 to10 carbon atoms that may have a substituent, linear alkenyl of 2 to 6carbon atoms that may have a substituent, branched alkenyl of 3 to 6carbon atoms that may have a substituent, linear alkyloxy of 1 to 6carbon atoms that may have a substituent, branched alkyloxy of 3 to 6carbon atoms that may have a substituent, cycloalkyloxy of 5 to 10carbon atoms that may have a substituent, a substituted or unsubstitutedaromatic hydrocarbon group, a substituted or unsubstituted aromaticheterocyclic group, a substituted or unsubstituted condensed polycyclicaromatic group, or substituted or unsubstituted aryloxy, where R₁ andR₂, R₂ and R₃, R₃ and R₄, R₆ and R₇, R₁₀ and R₁₁, and R₁₂ and R₁₃ maybind to each other via a single bond, substituted or unsubstitutedmethylene, an oxygen atom, or a sulfur atom to form a ring; and R₈ andR₉ may be the same or different, and represent trifluoromethyl, linearalkyl of 1 to 6 carbon atoms that may have a substituent, branched alkylof 3 to 6 carbon atoms that may have a substituent, cycloalkyl of 5 to10 carbon atoms that may have a substituent, linear alkenyl of 2 to 6carbon atoms that may have a substituent, branched alkenyl of 3 to 6carbon atoms that may have a substituent, linear alkyloxy of 1 to 6carbon atoms that may have a substituent, branched alkyloxy of 3 to 6carbon atoms that may have a substituent, cycloalkyloxy of 5 to 10carbon atoms that may have a substituent, a substituted or unsubstitutedaromatic hydrocarbon group, a substituted or unsubstituted aromaticheterocyclic group, a substituted or unsubstituted condensed polycyclicaromatic group, or substituted or unsubstituted aryloxy, which may bindto each other via a single bond, substituted or unsubstituted methylene,an oxygen atom, or a sulfur atom to form a ring.
 2. An organicelectroluminescent device that comprises a pair of electrodes, and oneor more organic layers sandwiched between the pair of electrodes,wherein the compound having an acridan ring structure of claim 1 is usedas a constituent material of at least one organic layer.
 3. The organicelectroluminescent device according to claim 2, wherein the at least oneorganic layer is a hole transport layer.
 4. The organicelectroluminescent device according to claim 2, wherein the at least oneorganic layer is an electron blocking layer.
 5. The organicelectroluminescent device according to claim 2, wherein the at least oneorganic layer is a hole injection layer.
 6. The organicelectroluminescent device according to claim 2, wherein the at least oneorganic layer is a light emitting layer.